Rod packing



March 21, 1939[ w. K. QUEEN 2,151,356

ROD PACKING Filed Jan. 25, L938 k/ENTE waltz. K- QM AT TEIRNELI:

Patented Mar. 21, 1939 PATENT OFFICE ROD PACKING Walter K. Queen, Needham, Mass.

Application January 25, 1938, Serial No. 186,766

3 Claims.

Myinvention relates to rod packing particularly adaptable for use in packing rapidly reciprocating rods against fluids under extremely high pressures. Heretofore I have employed for this purpose a packing comprising alternately arranged metallic and fabric packing rings, the metallic rings being formed of alloys usually employed for this purpose and the fabric rings being formed of woven asbestos treated in various ways, and such packing was satisfactory when used with rods having a fairly high rate of reciprocation and fluids of relatively high pressure.

Later when such a packing was used with the plunger of a pump, the actuating shaft of which had a rotary speed of 2,000 R. P. M., and the -pressure developed in the pump barrel was about 2,000 pounds per square inch at a temperature of about 240 F., it was found that the metallic rings were distorted'and the inner peripheries thereof extruded along the exterior surface of the shaft, thereby causing the practically complete destruction of the fabric rings.

An alloy containing lead is readily distorted and portions thereof may be extruded by blows from the pean or rounded end of a hammer, the pean denting the material and the metal surrounding the dent flowing outwardly or being extruded. It is quite desirable to use for the purpose above set forth, a metal bearing ring having a substantial percentage of lead, as hereinafter more fully set forth, and therefore it will be readily understood that such rings will be distorted and portions thereof extruded, by what practically amount to 2,000 heavy blows per minute, when used in the situation above specified.

In order to remedy this defect, I devised means for protecting the metallic rings from distortion and extrusion and thereby protecting the'fabric rings from destruction. In the present instance,

the protective means consist of relatively thin of a thin protective ring, a metallic ring, another thin protective ring, a fabric ring, a third thin protective ring, and so on throughout the packing. An illustrative embodiment of my invention is shown in the drawing which accompanies and forms a part of the present specification, in which I is a stuffing box provided with the usual gland '2, and 3, 4 are end rings or adapters, the ring 3 being formed with a cone shaped depression, and the ring 4 being conical, whereby there is formed between said rings a space adapted to receive the packing rings, each of which has the form of a truncated cone at one end and a cone shaped 5 depression at the opposite end.

The metal rings above described are shown at 5 and preferably consist of alloys of copper, zinc and lead, although I do not limit my invention to any particular alloy or to any combination of specified metals. I have found that excellent results are obtained by making the metallic rings 5 of Cadman metal, a well known article of commerce which comprises the following metals in substantially the proportions set out, viz., lead, about 80.1%, antimony, about 16.75%, copper, about .37 bismuth, about .13 and a hardener which may consist of tin and arensic in amount about 2.65%. The best results, however, are obtained when the metallic rings are made from said Cadman metal, to a given quantity of which is added a quantity of lead to the extent of about one quarter by weight of the Cadman metal, therebyincreasing the lead content of the latter.

It is to be understood, however, that my invention 5 is not limited to the alloy above specified and that the metal rings 5 may be made of any suitable alloy having a high lead content. The rings are relatively thick, being in the present instance about one quarter of an inch in thickness, they have relatively low tensile strength, relatively low shearing strength, and are non-flexible. The material of which they are made is capable of extrusion under pressure, chiefly because of the lead content thereof.

The fabric rings which are shown at 6 may be formed of woven asbestos which may be treated in any manner desired and provided with wire insertion. As many materials are suitable for such rings it will be understood that I do not limit my invention to any particular fabric.

The protective rings which are shown at l preferably are formed of an alloy of copper, 75%; nickel 20%; and zinc 5%; the melting point of which is about 2100 F. These rings, which are about .02 inch thick have the characteristics above specified and the material thereof cannot be extruded.

In the accompanying drawing I have shown a pair of rings '1 at each end of the packing, an arrangement that has proven satisfactory in practice. It will be obvious, of course, that more than two such rings may be used at the ends of the packing and that more than one such ring may be used to separate the proximate faces of each pair of packing rings. A rod packing, such as above described, successfully withstood a 2000 hour test in a pump having a plunger that made 4000 reciprocations per minute and in which a pressure of 2,000 pounds per square inch was developed on the discharge stroke, whereas in aprior test an identical packing without the protective rings 1 was completely destroyed after a relatively short period of use. The thin rings 1 protect the metal rings 5 from distortion and extrusion, and said rings 5 and I protect the interposed fabric rings from distortion so that the outer and inner peripheries thereof are maintained in condition to prevent the seepage of fluid between their outer peripheries and the inner wall of the stumng box and between their inner peripheries and the outer surface of the pump rod.

Having thus described anillustrative embodiment of my invention without, however, limiting the same thereto, what I claim and desire to secure by Letters Patent is:

1. A rod packing comprising a series of alternately arranged metallic and fabric sealing rings of substantial Width, and protective sealing rings interposed therebetween, said protective rings being formed of flexible material having tensile and shearing strength higher than that of said metallic rings and being much thinner than either said metallic or fabric rings.

2. A rod packing comprising a series of alternately arranged metallic and fabric sealing rings of substantial width, said metallic rings being formed of a material having a high lead content, and protective sealing rings interposed therebetween, said protective rings being formed of flexible material having tensile and shearing strength higher than that of said metallic rings and being much thinner than either said metallic or fabric rings.

3. A rod packing comprising a series of alternately arranged metallic and fabric sealingrings of substantial width, said metallic rings being formed of a non-flexible material, and protective sealing rings interposed therebetween, said protective rings being formed of flexible material having tensile and shearing strength higher than that of said metallic ringsand being muchthinner.

than either said metallic orfabric rings, ,1 

